Magnesium Die Casting In Automotive Applications New trends and innovations Meridian Technologies Manchester 24th 2008 www.meridian-mag.com
Meridian s Global Presence 2
MERIDIAN IN THE WORLD 5 manufacturing plants 7 Business development offices 1400 Employees 45.000 metric tons Mg 61 die cast cells (from 800t up to 3200t) Internal assembly and machining capability Turnover 2004 : 265 Millions 3
Major Magnesium Based Auto Products 4
Meridian key Products Instrument Panel Over 2,5 Millions per year Front End Carrier Over 0,9 Millions per year 4 Wheel drive transfer case Over 2 Millions per year Steering columns brackets Over 3 Millions per year Seats structure Over 0,4 Millions per year 5
Trends 6
Changes on the market - Cr Free corrosion resistant solutions (coated parts) => FEC - Low creep alloys with ductility, and good castability Engine Craddle (AE44) - Higher corrosion resistance of AE44 No coating on Engine Craddle - Higher Al cost Powertrain (Oil pans, brackets) 7
Front End structure Weight saving (50%) Stiffness (torsion) Fit and finish Air flow Corrosion (cosmetic) Relaxation/joints (100 C) Crash 8
Corrosion - General corrosion => No issues (no coatings on parts, ex: gear boxes) => High purity alloys => if cosmetic => coating 9
Corrosion - General corrosion => No issues (no coatings on parts, ex: gear boxes) => High purity alloys => if cosmetic => coating - Galvanic corrosion => Needs to be addressed 10
Corrosion Galvanic (structural) => Drain and insulate 11
Drainage Poor Better Design for corrosion Best Steel Drainage Mag Aluminium spacers 5000 series aluminum spacer Dissimilar metal mating part Drain holes greater then 10mm Ø 12 Magnesium part Lip added to aluminum insulator to break bridging
Joining with steel bolts Steel Coating Zn/Ni + Xylan Aluminium 5000 Series black anodised Washers 10 mm Coated AM 60 B Magnesium Plaque www.meridian-mag.com
Coating? No cosmetic requirement No cosmetic requirement No cosmetic requirement 14 Cosmetic requirement
Coating? Cosmetic requirement No cosmetic requirement Cosmetic requirement 15
FEC development Production Physical validation Development 9 4 5 7 1 1 1 2004 2007 2009 16
Engine Cradle Engine Cradle -Temperature (150 C) - Crash requirements Low creep alloys - No corrosion pre-treatment 17
HISTORY: Project Started as a USCAR Project (United States Council for Automotive Research). Low creep alloys evaluated in terms of: - Castability (thin/thick walls vs. AZ91) - Properties (static, fatigue, creep, corrosion) Involved General Motors. Ford and Daimler Chrysler Development vehicle: The 2006 high performance variant of the General Motors Corvette known as the Z06 18
19
Alloy drivers: - Temperature (125 C) - Crash AE44 A%: 9-10 % ; YS: 125 MPa ; UTS: 230 MPa Base: A356 LPDC vacuum 13% elongation Design drivers: - Stiffness - Fatigue - Load & Strength Engine cradle Drivers 20
Future opportunities? 21
RheoDiecasting Clamping unit Inlet Twin-screw extruder T/C T/C Die High speed injection unit Professor Z Fan (Fan) BCAST (Brunel Centre for Advanced Solidification Technology) Brunel University 22 UK
The conventional HPDC process Hydraulic clamp Shot sleeve Piston Die 23
Rheo-diecasting (RDC) process Clamping unit Twin-screw extruder Inlet T/C T/C Die High speed injection unit Rheo-diecasting = Slurry maker + HPDC 24
Microstructure of rheo-diecast AZ91D parts 25
Property comparison with other processes (AZ91D) 275 250 Thixo-c RDC UTS (MPa) 225 200 175 150 HPDC Thixo-m 125 0 2 4 6 8 Elongation (%) 26
Microstructure of rheo-diecast AZ91D alloy (Well dispersed fine oxide particles) 27
Summary Fine and uniform microstructure throughout the parts Improved mechanical properties Higher integrity (<<1% porosity) thus heat treatable Verify welding Thin / Thick walls capability? Tighter dimensional control Longer die life 28
To be tested and characterized at Meridian Including component tests in 2007 29
Conclusions New trends and innovation: - Front end carriers - Engine cradles - Powertrain applications - Corrosion solutions - Low creep alloys for crash components - Development of fixing - RheoDiecasting potential 30